[PATCH V2] net: qrtr: Do not do DEL_SERVER broadcast after DEL_CLIENT

From: Sricharan Ramabadhran
Date: Fri Mar 31 2023 - 03:51:36 EST


On the remote side, when QRTR socket is removed, af_qrtr will call
qrtr_port_remove() which broadcasts the DEL_CLIENT packet to all neighbours
including local NS. NS upon receiving the DEL_CLIENT packet, will remove
the lookups associated with the node:port and broadcasts the DEL_SERVER
packet.

But on the host side, due to the arrival of the DEL_CLIENT packet, the NS
would've already deleted the server belonging to that port. So when the
remote's NS again broadcasts the DEL_SERVER for that port, it throws below
error message on the host:

"failed while handling packet from 2:-2"

So fix this error by not broadcasting the DEL_SERVER packet when the
DEL_CLIENT packet gets processed."

Fixes: 0c2204a4ad71 ("net: qrtr: Migrate nameservice to kernel from userspace")
Signed-off-by: Sricharan Ramabadhran <quic_srichara@xxxxxxxxxxx>
Signed-off-by: Ram Kumar Dharuman <quic_ramd@xxxxxxxxxxx>
---
[v2] Fixed comments from Manivannan and Jakub Kicinski
Note: Functionally tested on 5.4 and compile tested on 6.3 TOT

net/qrtr/ns.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/net/qrtr/ns.c b/net/qrtr/ns.c
index 722936f..0f25a38 100644
--- a/net/qrtr/ns.c
+++ b/net/qrtr/ns.c
@@ -274,7 +274,7 @@ static struct qrtr_server *server_add(unsigned int service,
return NULL;
}

-static int server_del(struct qrtr_node *node, unsigned int port)
+static int server_del(struct qrtr_node *node, unsigned int port, bool bcast)
{
struct qrtr_lookup *lookup;
struct qrtr_server *srv;
@@ -287,7 +287,7 @@ static int server_del(struct qrtr_node *node, unsigned int port)
radix_tree_delete(&node->servers, port);

/* Broadcast the removal of local servers */
- if (srv->node == qrtr_ns.local_node)
+ if (srv->node == qrtr_ns.local_node && bcast)
service_announce_del(&qrtr_ns.bcast_sq, srv);

/* Announce the service's disappearance to observers */
@@ -373,7 +373,7 @@ static int ctrl_cmd_bye(struct sockaddr_qrtr *from)
}
slot = radix_tree_iter_resume(slot, &iter);
rcu_read_unlock();
- server_del(node, srv->port);
+ server_del(node, srv->port, true);
rcu_read_lock();
}
rcu_read_unlock();
@@ -459,10 +459,13 @@ static int ctrl_cmd_del_client(struct sockaddr_qrtr *from,
kfree(lookup);
}

- /* Remove the server belonging to this port */
+ /* Remove the server belonging to this port but don't broadcast
+ * DEL_SERVER. Neighbours would've already removed the server belonging
+ * to this port due to the DEL_CLIENT broadcast from qrtr_port_remove().
+ */
node = node_get(node_id);
if (node)
- server_del(node, port);
+ server_del(node, port, false);

/* Advertise the removal of this client to all local servers */
local_node = node_get(qrtr_ns.local_node);
@@ -567,7 +570,7 @@ static int ctrl_cmd_del_server(struct sockaddr_qrtr *from,
if (!node)
return -ENOENT;

- return server_del(node, port);
+ return server_del(node, port, true);
}

static int ctrl_cmd_new_lookup(struct sockaddr_qrtr *from,
--
2.7.4